Tracing the three-dimensional nanochemistry of phase separation in an inverse Ni-based superalloy

Hierarchical microstructure strengthening in a single crystal high entropy superalloy

“…In a previous work on Ni 86.1 Al 8.5 Ti 5.4 alloy 44,51,52 , the FCC particles could coarsen into directional plates in the L1 2 matrix after prolonged ageing at 1,023 K. Meher et al 45 also found that ageing at 1,073 K could coarsen www.nature.com/scientificreports/ the FCC particles and decreased its fraction significantly. In this work, since the FCC particles in the L1 2 phase were in metastable states, all the FCC particle forming elements would diffuse across the L1 2 phase into the surrounding FCC matrix after prolonged ageing, so that the whole system could reach the equilibrium state, Fig.…”

“…In the future, metastable FCC matrix channel should be explored further by heat treatment design to investigate if additional hierarchical microstructure strengthening can be achieved. To the best of authors' knowledge, only few literatures have reported the dispersion of FCC particles in L1 2 matrix [44][45][46] . Vogel et al 44 studied FCC particles in Ni 78 Al 13 Ti 9 L1 2 matrix alloy with the partitioning coefficients of Al (0.6), Ti (0.42) and Ni (1.14); Ni showed preferential partitioning toward FCC phase, and high Ni content in the L1 2 phase was deduced to be responsible for the FCC particle formation.…”

“…There is a very limited number of papers reporting benefit of the kind of hierarchical microstructure by experiments 44,45,[52][53][54][55][56][57][58][59] . Vogel et al 44 showed a 50 HV hardness increase with the presence of FCC precipitates in Ni 78 Al 13 Ti 9 44 L1 2 matrix alloy. In addition, Tian et al 54 reported a 78 MPa increase in compression strength at 973 K by the FCC precipitation in Ni 78 Al 18 Ti 4 L1 2 matrix alloy.…”

“…To the best of authors’ knowledge, only few literatures have reported the dispersion of FCC particles in L1 2 matrix 44 – 46 . Vogel et al 44 studied FCC particles in Ni 78 Al 13 Ti 9 L1 2 matrix alloy with the partitioning coefficients of Al (0.6), Ti (0.42) and Ni (1.14); Ni showed preferential partitioning toward FCC phase, and high Ni content in the L1 2 phase was deduced to be responsible for the FCC particle formation. Meher et al 45 designed a Re and Ru bearing Ni-based superalloy, and FCC particle dispersion in L1 2 phase was found within the dendritic microstructure; the supersaturation of Co, Re and Ru in the L1 2 phase was suggested to be the driving force for the formation of FCC particles.…”

A first-principles phase field method for quantitatively predicting multi-composition phase separation without thermodynamic empirical parameter

“…Vogel et al 20 showed γ -Ni particles in the γ ′-Ni 3 Al precipitates in hierarchical microstructures of Ni–Al alloy. A very recent paper 21 established an analogy between the inverse alloy and the hieirarchical Ni 86.1 Al 8.5 Ti 5.4 alloy. Therefore, we believe that the prediction of such an inverse alloy will be seen in experiments too.…”